The game continues the series' theme of comical sports as the player takes the role of a boxer who makes his way from his debut to become a world champion. The player can choose from several different types of punches and defensive maneuvers, along with unique special attacks. The player revives their stamina during the round interval by pressing the button rapidly.

The boxer's abilities are determined by three different stats; punch, stamina, and speed. The player can improve these stats using the power points gained after each match. Performing well in matches allows the player to create more powerful boxers. The player can save their game progress by recording a password, and two players can face off against each other in the two-player mode. Though the game is rudimentary, it is possible to counter-punch, and missing with too many punches causes the boxer's stamina to decrease.

The biggest characteristic of the game is the comical set of special attacks. These moves are activated when the player presses the attack button at the right timing and at the right distance. The attacks have the capability to instantly knock out the opponent, but being countered before a special attack causes an extraordinary amount of damage as well. The first special attack is a powerful hook which the boxer throws by spinning around like a top. The second is a straight punch that propels the opponent into the ropes when it connects. The third type is an uppercut that launches the opponent straight into the air. If thrown at the right timing, the uppercut can blast the opponent straight out of the ring, resulting in a technical knockout

The NES/Famicom version of Ring King/Family Boxing created some controversy because the boxers' cornermen appear to be performing fellatio on them between rounds. Though the scene was only intended to show the cornermen placing the Foul Cup into the boxer's trunks, the graphical limiations of the NES made the scene appear questionable. The boxers may also appear to be hugging as they grapple because of the game's poor graphics.